<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>梯形和三角形</title>
  <style>
    .trapezoid {
      width: 60px;
      height: 60px;
      border: 100px solid transparent;
      border-bottom-color: pink;
      margin: 100px auto;
    }

    .triangle {
      width: 0;
      height: 0;
      border: 100px solid transparent;
      border-bottom-color: skyblue;
      margin: 100px auto;
    }
  </style>
</head>
<body>
  <div class="trapezoid"></div>
  <div class="triangle"></div>
</body>
</html>